Dell PERC H310 mini support 12Gb/s Internal SAS?

[fahadshery]

Hi,

I am upgrading my TrueNAS game and got a Dell R720 server. I have installed a Dell PERC H310 mini controller for the SAS drives. The question is will it work if I buy Toshiba or HGST 12GB/S SAS drives? Will I gain any performance improvements over 6GB/S drives?

Cheers,

 

[jgreco]

There are no "12GB/S" or "6GB/S" hard drives. A capital "B" is bytes. Please review the Terminology and Abbreviations Primer, which helps us all communicate more effectively.

In this case it's pretty clear that you mean "12Gbits/sec" or "6Gbits/sec" (or Gbps), but I'll make a little point here in a moment that shows why this pedantry is actually important.

A modern hard drive has an average transfer speed in the range 200MB/sec-250MB/sec. The capital-"B" definitely means bytes, and most tools measure drive speed in this manner. However, if you convert these numbers to bits-per-second, you end up at 1600Mbits/sec-2000Mbits/sec, or 1.6Gbits/sec-2Gbits/sec. This is barely more than original SATA speed (1.5Gbps), and less than original SAS speed (3Gbps).

A 2Gbit/sec drive will not go noticeably faster on 12Gbit/sec connectivity than 6Gbit/sec. There may be the teeniest bit less latency, never anything a human could notice, but you could probably measure it in a lab.

I would be more concerned about cabling and backplanes. In theory, you should be able to connect a 6Gbps device to a 12Gbps device and have it work. However, 6Gbps SAS often uses SFF-8087 while 12Gbps SAS often uses SFF-8643, so there is a physical connector difference that may make a difference if the R720 had previously been outfitted with a 12Gbps controller, and you are trying to replace it with an H310. The Dell stuff also has a tendency to have special stuff baked into the firmware to work with their stuff, so it is possible you might find that you need to acquire a Dell version of the LSI 3008 HBA (9340-8i) instead. 12Gbps SAS drives should work fine though.

 

[fahadshery]

There are no "12GB/S" or "6GB/S" hard drives. A capital "B" is bytes. Please review the Terminology and Abbreviations Primer, which helps us all communicate more effectively.

Noted :)
Yes, It's Gbits/sec.

A 2Gbit/sec drive will not go noticeably faster on 12Gbit/sec connectivity than 6Gbit/sec. There may be the teeniest bit less latency, never anything a human could notice, but you could probably measure it in a lab.

It's good then coz I haven't bought those yet. I think, I should just stick to 6Gbit/sec ones.

I would be more concerned about cabling and backplanes. In theory, you should be able to connect a 6Gbps device to a 12Gbps device and have it work. However, 6Gbps SAS often uses SFF-8087 while 12Gbps SAS often uses SFF-8643, so there is a physical connector difference that may make a difference if the R720 had previously been outfitted with a 12Gbps controller, and you are trying to replace it with an H310. The Dell stuff also has a tendency to have special stuff baked into the firmware to work with their stuff, so it is possible you might find that you need to acquire a Dell version of the LSI 3008 HBA (9340-8i) instead. 12Gbps SAS drives should work fine though.

Mine came with PERC 310 mini already installed which I am thinking to put in IT mode. There are so many guides out there to do so but I am not sure yet which one to follow. If you know any then I would appreciate it.

Thanks for taking the time to answer this in depth.

 

[jgreco]

Mine came with PERC 310 mini already installed which I am thinking to put in IT mode.

Well that solves any cabling issues. You do need it in IT mode with 20.00.07.00 firmware, though.

There are so many guides out there to do so but I am not sure yet which one to follow. If you know any then I would appreciate it.

Sorry, no. I do this professionally and we have a process here in the shop for these, but it is dependent on local toolsets, the PXE environment, and some machines known to work correctly. I can't really evaluate the accuracy of any of the guides out there, but I *can* tell you that in my experience it is really tough to totally trash an LSI HBA to the point where it cannot be recovered, so if you follow a guide and you get stuck, don't panic or freak out, and there are lots of people who have some vague idea of how this all works and can help you out. Worst case, what's a new H310 mini cost?

Thanks for taking the time to answer this in depth.

Just lookin' for the successful outcome. Feel free to report back on how it goes.